Engine having alternate internal-combustion and fluid pressure power strokes



ar 1954 H. ROHRBACl-k 2.671.311

ENGINE HAVING ALTERNATE INTER AL-COMBUSTION AND FLUID PRESSURE POWER STROKES 2 Sheets-Sheet 1 Filed March 16, 1951 3.5 I 29 a0 a2 51 m F 36 if 19 36 13' l I Q Q; I

[Hz 5172b!" HazzaEa/mbac/z March 1954 H. ROHRBACH ENGINE HAVING ALTERNATE INTERNAL-COMBUSTION AND FLUID PRESSURE POWER STROKES Filed March 16, 1951 2 Sheets-Sheet 2 fjg fig/f6 Patented Mar. 9, 1954 EN WE HAVI G LTE A N AL- ooMBUs-TioN AND FLU-In PRESSURE POWER STROKES Ban Bo ha h, lt r lamina Switz rlensl e s gn r o one-thi to J Re l Element Ill and one-third to Otto Brenneman, Bart- Application Manchslfi, 1951, Serial No.15,88.5

Sw ss- 1 The present :ileilfim qn rela e to m thod o enera-ting p er o t o impro e engine essembly.

in ordinary combu tio -en ne whe he -e teline eng nes operating n on ntionam e o diesel en in s, a lar e zre enteae o th hea generated by the "com nstion of the tuel is lost and does no use ul tors In ta t, z-m en ar ordinarily nrotzided for dissipating the vheat genera-ted in the combu tio er s as nu' lr ly a "possible op ent overh at h io linder wa l Ordinarily, about 30 to 35% of the heat liberated upon combustion o tota ie sipated ra ter o -.bustion with th resul th rcom sti n n ine ldo not atta efilmeney h gher tha ab 35 calculated on h availabl met- In the present invention, means are provided {or recovering useful :wqrk from the heatlof the combustion gases While at the same time lineyenting overheating of the. cylinder Walls durin operation of the engine.

Basically, the engine of the-present invention is ;a modified diesel-type-,- engine in which ork is derived from-the combustible fuel, and in which a liquid coolant material is periodicallyinjected 2111170 the combustion chamber. 'Ijhe coolant :SGI'VBS the vdual function-of .cooling the combustion chamber by the evaporation of ,the ;liquid fi f the :form tap end s ondly. the rapid expansion of the liquid coolant due to the heat of th -'eombu t onch m e se urn th l o iorasecondwork stroke.

Contrary to o di ar pract e the o bu tion chamber-jOf' hfl mi? QY ;i ini /11 1 yided with heat dissipating means, but is 9110- -;vided with thermal insulation ;;t;o retain gas nn oh :of the heat .:as;possiblein the ;cornbustion c nber. The "heat present in :the {chamber ii'zhen adequate to avaporize the :liquid rcool lnt rapidly upon injection thereof intosthe chambertozproivide thesecond-work-stroke by: expansion .Of the (coolant.

1W hile several modified procedures are possible in the i method of the present invention, gas {will :be @hereinafter explained, in-thepreferrfil em- :bo'dimentof :the invention, :the yfirst v cycle of operation of the engineinvolvesthe combustionof a combustible fuel in the cylinder :to do Work upon the reciprocatinglpiston;contained;;therein. The --residual gases resulting from combustion, consisting primarily of nonecondensable gases :are {then at least :nartially vented into heat .exchange relationship .With a liquid coolant materialsuch-as water. In this heatlexchangergthe water-is undersubstantial, pressuramndgiswaised em un of t en sen ed in the eat to tenrerat ee we above its boiling point at atmospheric pr ess ur e wh le st ll rema eiegin inla fitt st?- he ted li uid water that ini'e tee int t aim- ,bustiqn eea e and tim o h hi h h a sentien o the i qmb s n sta e is ra dly o et lize nt a substantially dry' steam. By the term fsypere ed" a s s thisispetifl et oa li e r t h tem e u e 4 missile the eplan ar su i ier t t ke th tenan s ite -t nt ll in liquid phase, so that upon injection of the coolant into the combustion space, the liquid is rapidly rq i ize ue t the Qll' lilfi tempe eteree -ii e e c nd tion more. l the $2 bi l tion sp ce I is x9lati1iza 9e er .tosn l th r a e th meme ,eediprz r sle to; ereby n t al z the 9l ei9t1 e i qr iine. by edate withtszo me ee ta p ratwein the tilinder.

.A e ewe ra id rel t liz i en .9? t c ol nt a e Jet? steam su s enou R1195- Vsu a n the piston head i. t e nei n xel in ther wo stroke The new stem and an re ides! mb stion e p esen ar nest d into b et l xe leng realitie- Ship with new be ore l etn s i ti n qf vtbeei into th com ustion e A substan in time exhaus ases t u =9te t 'tl ie y .uee' i unc on o z ehee i s th inle a r During t heat int r h n e t e e t em exhau te the th t o b stis nham er i some-tees n at e z asse lamentab e hum int an rator Where air and other gases lielnai ning in he ten ons ed i quiea rented Th li d reme .eiee in the ai ten-fine uni he pre nte b ui able lee-m l ud e sees in ne 42 change relationship with the oornbustiqn gases-to superheat the liquid goolant griorto 'njeotion in the eemb sti n trees a previo sly l xolainedthus th newe generating system 9 th presen in ent. n :R EWZ E e t o ed ey te to opola mat. al s n e the i q le 'exhe is e tram th qiil u ns ep int mate ireq er e eenes u eti .d ticni hem e z nth -th le lq p en is practically negligible.

ilaflb fict of {the nresent inuentionis to provide za meth do ieeneret nei we in wh b hehe contained th .qqmbrst e eases f resem le ;ti nene neit :re were itwo uteiu -wo k- Another 'plbieet o :th meet? in tio i t arouse Montp ie nete i zp uen whiq a liquid coolant is mates Quietl nter? 911 whitewatebustion chamber to cool the chamber while at the same time providing a second work stroke by the expansion of the coolant.

Still another object of the present invention is to provide a method for generating power in a modified diesel-type engine.

Another object of the present invention is to provide a method for increasing the efficiency of combustion engines.

Still another object of the present invention is to provide a, power generating system containing means for generating power due to the combustion of a combustible fuel alternating with work strokes derived from the expansion of a liquid coolant material.

Another object of the present invention is to provide a modified diesel engine with an auxiliary steam generating system to provide additional power strokes in the diesel engine.

Another object of the present invention is to provide a diesel engine of substantially increased efficiency.

Another object of the invention is to provide an internally cooled combustion engine in which the coolant passes through a closed circulating system, thereby minimizing losses of the coolant material.

For a further explanation of the method and apparatus of the present invention, reference is made to the attached sheets of drawings in which:

On the drawings:

Figure 1 is a schematic representation of the power generating system of the present invention illustrating the components thereof and the flow of the various streams through the system;

Figure 2 is a fragmentary view of the combustion chamber illustrating the position of the elements during injection of fuel in the chamber;

Figure 3 is a fragmentary view similar to Figure 2 and illustrating the condition of the combustion chamber after combustion of the fuel during the return stroke of the piston;

Figure 4 is a fragmentary view illustrating the condition where the liquid coolant material is injected into the combustion chamber;

Figure 5 is a fragmentary view of the combustion chamber at the time the expansion of the coolant has provided a second work stroke;

Figure 6 is a fragmentary view similar to the aforementioned views illustrating the condition of the combustion chamber at the end of the cycle in which the vaporized coolant material has been exhausted; and

Figure '7 is a fragmentary view of the combustion chamber illustrating the introduction of air into the chamber prior to injection of fuel as shown in Figure 2.

As shown on the drawings:

The system shown in Figure 1 includes a cylinder assembly whose hollow interior defines a combustion chamber l I. A relatively small piston l2, provided with piston rings I 3 engaging the walls of the cylinder I0, is mounted for reciprocation within the cylinder Ill. The piston l2 carries a wristpin l4, the latter being coupled by means of a connecting rod l to the engine crankshaft l6, as shown.

The inner walls of the cylinder It], generally indicated at l8, are preferably provided with good heat conducting surfaces, as by electroplating or depositing a thin layer of copper on the surfaces. Alternatively, the cylinder assembly It! can be provided with a copper bushing in which the piston I2 reciprocates. r

To minimize the possibility of oxidation of the piston head during operation of the engine, the piston head I9 is preferably provided with a corrosion-resistant coating, such as chromium plating.

sides in providing heat insulating means to retain as much of the heat of the combustion gases in the combustion area as possible. In the assembly shown in Figure l, the heat insulating means includes a jacket 2| which surrounds the combustion chamber, leaving an evacuated space 22 between the walls of the jacket 2| and the walls of the cylinder ID. The inner surface of the jacket 2|, indicated at 23 may also be provided with a silver coatin to minimize heat radiation losses. In effect, then, the combination of the outer jacket 2|, the silver-coated surface 'on the wall 23 and the evacuated space 22 are arranged to preserve the heat within the combustion chamber in the same manner that a thermos bottle preserves the heat of its contents.

The combustion space I l is supplied with air by means of a conduit 25, through an inlet port 60, the control of the flow of air being maintained by means of a, valve element 26 bottomed against the cylinder wall. An exhaust port 6| communicates with an exhaust conduit 21 which together with an exhaust valve 28 exhausts the combustion gases and vaporized coolant from the combustion space H after the various work strokes.

A conduit 29 supplies a combustible fuel to the combustion chamber, the supply of fuel being regulated by a needle valve element 30. Another conduit, 3!, supplies a pressured liquid coolant into the system, the control of the flow of the coolant material being governed by another needle valve element 32.

The flow of the gases exhausted from the combustion chamber H is regulated by means of a two-way valve 34 in the exhaust conduit 21. In the position of the valve 34 illustrated in Figure 1, steam, or other volatilized coolant exhausted from the combustion chamber H is passed by means of a steam escape line 35, in the direction of the arrows, to a condenser assembly indicated at 36. In the condenser 36, the steam passes into countercurrent heat exchange relationship with a supply of fresh air being directed into the condenser 36 from an inlet port 31. Due to the exchange of heat between the relatively cool air and hot steam in the condenser 36, the steam is condensed and the air is substantially heated prior to introduction into the combustion chamber. The air after passage through the condenser 36 is passed into a supercharger 38 which further compresses and heats the air prior to its introduction into the combustion chamber H by means of the conduit 25.

The condensate resulting from the condensation of the steam in the condenser 33 is passed by means of a conduit 39 into an air separator unit 40 by the action of a condensate pump 4|. In the air separator 40 the condensate forms a liquid reservoir 42, while air, or other noncondensable gases contained in the steam leaving the combustion chamber 1 I are vented to the atmosphere by means of a vent 43.

The liquid 42 present in the air separator is continuously withdrawn therefrom through a conduit 44 by means of a water pump 45. This pump pressures the liquid water to a relatively high superatmospheric pressure on the order of atmospheres. The pressured water then is One of the features of the present invention remumped through a conduit &6 into a "heat exchanger '41, "where its temperature is -raise'd to a qmint well above its boiling point a't atmospheric pressure. Atypical value for the temperature of the water leaving the heat exchanger 41 is in the vicinity of 800 C. "Fhe superheated *liquid Water Heating the heat exchanger 4 iis then "introduced "into the combustion ohamber 1 during an -appropriate :portion 'of the cycle bymeans of the ozonduit 3 and va1ve=element -32.

Heat exchange "is efieoted in the heat exchanger '41 by passing the pressured =w-a'ter into courltercurrent heat exchange relationship with =the non-condensable exhaust gases =-produeed in *the combustion cl'rarriber 5H =during combustion "of the fuel. These gases are directed through the exhaust conduit 21, and when the valve -34 has been 'rotated at "90 in a counter-clockwise direction from *the :position shown in Fig. 1, *through a line 50 into "the heat exchanger W1. "During-the heat =ex0hangeprocess, the water, 'as -previously mentioned, is heated-to a temperature "of -about 800 while the exhaust gases may fbe 'eooled -by about 100 C. After such cooling, the eases are vented through an eiihaust :p-ort 6 1 in the *heat exchanger WI.

The timing of :the eneine and the time of introduction of the fueljintro'ductiomof cool-ant, eand-exhaust =of the gases-may be waned -consid- =erably. *Phuspitwill not always be essential that 'each work stroke from the combustion of fuel =be followed'by an inj action-of "coolant -materia1. "In ather-words, several work strokes eambe "had =from the=fuel combustion beforeinjection-of the -=eoolant *material, if the conditions in the cylintier permit *such *hieh temperature operation. The alternate injection of fuel and coolant is, however, -'preferred, 'and it is this embodiment which is-iliustrated in Figures-2-'7.

In the system 'shown in *Fig. -2, the *air =inlet valve 26 closes the air "inlet port'tfl and the exhaustvalve zd oloses'the exhaustrport ei. "The "combustion chamber H -contains a supply -01 heated air whichhas-previously been compressed by the motion of the piston 12 into its-top-dead mentor position illustrated in Fig. 2. *In this #position, fuel is introduced =into "the combustion space H by opening ofthe "needle valve element 30. Buring this cycle, *the needle valve -*32 'gov- *erning the introduction of superheated 'water, is, of =course, closed.

As the fuel is introduced into the omnibus- "tion 'ohamber I I it forms an :explosive mixture with the *air "previously introduced and becomes detonated by *the heat contained within the combustion "chamber. 'The resulting rapid ex- 1351181011 ofthe-oombustiongases thereupon-forces the piston "l2 downwardly to its *bottom dead "center position illustratedin Fig. 3. "Near the time' the piston 2' reaches its'jbottom deadcenter position the exhaust valve "28 'is opened. Permit- =ting-the combustiongases to escape 'fromthe combustion chamber H through the 'exhaust port 6|. These gases are then -vented "by-means of the conduit '50 '(Figrl) into. heat exchangereia- .tion'ship with the superheated water being pumped into the heat exchanger Mto superheat "the water and "to recover some of the "sensible 'irheat of .the exhaust gases.

"In'the next cycle of1the .operationyillustrated in Fig. 4, the piston 12' is in" itsupper dead'center position after exhausting the gases"throughthe exhaust port 61. In this ;-position, "the ;needle waive 32 :is #qnenefd to ';inject superheated water I "into "the -oon'rbust'ron chamber H. =Because "the center position. Alt this time, the needle valve -32 has been closed-and the exhaust -va1ve 28ils opened "to exhaust the residual steam :irom :the combustion chamber. The 'steam :does not condense within the chamber :because of the large amount of'heat stored *in the combustion :cham- "beryeventhoughsome of this heat is absorbed -ln =vola-ti1izing the liquid water into steam. 'The steam, air, :and any residual non-condensable gases are vented :during this cycleibymeans'of the valve 3'4 (Fig. 1) through the conduit 35 and into the condenser -36 where the steam is :condensed' byrheat 1 exchange :with the relatively cool air-supply being introduced into the condenserifi.

After completion "of the steam :exhaust -st-roke, =each of-the valvesis closed, as illustrated-in Fig. 6, and also illustrated in Fig.1. Duringthe next downward stroke of the piston =12, compressed air is injected into the inlet :port (it! ='from the supercharger 35, upon the :opening of the air inlet valve 26. This condition is illustratediin Fig. 7 of the drawings. liiuringrthe noxtmpward stroke of the piston Fl the '-hot--=air'-is further compressed prior to the introduction or '-fuel through the fuel inlet system, as illustrated :in Fig. 2. This, them-completes the cycle'inwhich the engine is 'first operated by a fuel combustion stroke and subsequently by 'a "steam expansion stroke.

Various modifications can "be ma'de in the method of operating the engine "previously described. For example, in the stroke during which the combustion gasesareexhausted, all of-the combustion-gases need not beexhausted, and-the exhaust valve 28 may be opened only momentarily during the upward 'stroke of the piston. *Under these' conditions-superheated wateris-in- 'jeotedinto the "hot combustion gase during-the water injection cycle.

Further, the engine oan beoperated' with-only a single exhaust stroke,by keeping "theexhaust -valve -28-entirely closed after the initial combustion'stroke. Alkofthe combustion gases will then be compressed upon the upward movement of the pistonand eommingled with the vaporized "steam :a'fter *the injection of superheated-waften e f steam nd combustion gases is *then exhausted after thesteam expansion; stroke, -asi1lustratedrin Figf5. v

Nor is it necessary'ithatithe intake -valve 32- for the coolantbe npenedmreciseiywvhen 'thef plston ti? readhesyitsunper dead'center position. {The engine ;can be timed so that "the "coolant is injectjed when the ypiston {is in its bottom -dead -center;positio1 1::so"that the vaporizingwater-will aizisorb' heatifrom the "entire cylinder-area rather than "from the region immediately adjacent "the "oylind-enhead.

In additionysuperheated water is not 'the only coolant material which could "be :employed. Coolants 'such as "ammonia, alcohol, "other, ;and even liquid air "could-also beemployed.

The design of the cylinder can ,also be "varied within limits. When "thin wall cylinders are em loy d,zabi herzeificiency.resultsih causeith -cylin'ck-zr "can "attain higher temperatures more rapidly and thereby provide for more rapid generation of steam within the combustion chamber. However, when using thin walled cylinders, the amount of steam generated is comparatively small. When using relatively heavy walled cylinders, more fuel injections can be made between each injection of the coolant because the cylinder walls can absorb more heat and accordingly produce a greater amount of steam.

It will be noted that operation in the manner previously described, when only one exhaust stroke is used to exhaust th mixture of burned gases and steam, results in the operation of the engine as a three cycle engine because there are two work strokes for every six strokes of the piston. This system has the advantage that the exhaust is rendered practically smokeless because of the steam present in the exhaust gases. When using this system, means are provided to condense the steam present in the exhaust gases after heat exchange with the superheated water. Otherwise, the system is the same as that illustrated in Fig. 1 in that the exhaust gases are alternately vented to preheat the air and then to heat the water under pressure entering the combustion chamber.

It will be evident that various modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In a power generating system, a combustion chamber, a piston reciprocable in said combustion chamber, means for introducing a combustible fuel into said chamber, air inlet means associat-.

ed with said combustion chamber, gas exhaust means associated with said combustion chamber,

a condenser, a heat exchanger, means for selectively directing a condensable exhaust gas from said gas exhaust means into said condenser and a non-condensable gas mixture into said heat exchanger, means for introducing air into said condenser to heat said air by heat exchange with the condensable gases being condensed therein, means for directing the condensate from said condenser into heat exchange relationship with said non-condensable gases flowing through said heat exchanger, and means for introducing the heated condensate from said heat exchanger into said combustion chamber.

2. In a power generating system, a combustion chamber, heat insulating means disposed about said combustion chamber, a piston reciprocable in said chamber, means for introducing a combustible fuel in said chamber, air inlet means associated with said combustion chamber, gas

exhaust means associated with said combustion chamber, a condenser, a heat exchanger, means for selectively directing a condensable exhaust gas from said gas exhaust means into said condenser and a non-condensable gas mixture into said heat exchanger, means for introducing air into said condenser to thereby heat said air by heat exchange with the condensable gases being condensed therein, means for directing the condensate from said condenser into heat exchange relationship with said non-condensable gases flowing through said heat exchanger, and means for introducing the heated condensate from said heat exchanger into said combustion chamber.

3. In a power generating system, a combustion chamber, heat insulating means disposed about said combustion chamber, a piston reciprocable in said chamber, means for introducing a combustible fuel in said chamber air inlet means associated with said combustion chamber. gas exhaust means associated with said combustion chamber, a condenser, a heat exchanger, means for selectively directing a condensable exhaust gas from said gas exhaust means into said condenser and for directing a non-condensable exhaust gas from said combustion chamber to said heat exchanger, means for introducing air into said condenser to heat said air by heat exchange with the fluid flowing through said condenser, means for directing the heated air into said air inlet means, means for pressuring the condensate from said condenser, means for directing the condensate into said heat exchange zone into heat exchange relationship with the non-condensable gases flowing therethrough, and means for introducing the heated condensate from said heat exchanger into said combustion chamber.

4. In a power generating system, a combustion chamber, a heat insulating means disposed about said combustion chamber, a piston reciprocable within said chamber, means for introducing a combustible fuel into said chamber, air inlet means associated with said combustion chamber. means for introducing a combustible fuel into said chamber, air inlet means associated with said combustion chamber, gas exhaust means associated with said chamber, a condenser, a heat exchanger, means for selectively directing a condensable exhaust gas from said gas exhaust means into said condenser and for directing a non-condensable exhaust gas into heat exchanger, means for introducing air into said condenser to heat said air by heat exchange with the the fluid flowing through said condenser, means for directing heated air into said air inlet means, means for pressuring the condensate leaving said condenser, means for separating condensable gases from said condensate, means for directing the condensate into said heat exchange zone into heat exchange relationship with the non-condensable gases flowing therethrough, and means for introducing the heated condensate from said heat exchanger into said combustion chamber.

5. In a power generating system, a combustion chamber, a heat insulating jacket about said chamber, said jacket being spaced from said chamber to provide an evacuated passage between said jacket and the walls of said chamber, a piston reciprocable in said combustion chamber, means for introducing a combustible fuel into said chamber, air inlet means associated with said combustion chamber, gas exhaust means associated with said combustion chamber, a condenser, a heat exchanger, means for selectively directing a condensable exhaust gas from said gas exhaust means into said condenser and a non-condensable gas mixture from said chamber to said heat exchanger, means for introducing air into said condenser to heat said air by heat exchange with the condensable gases being condensed therein, means for directing the condensate from said condenser into heat exchange relationship with said non-condensable gases flowing through said heat exchanger, and means for introducing the heated condensate from said heat exchanger into said combustion chamber.

6. In a power generating system, a combustion chamber, a heat-insulating jacket about said chamber, said jacket being spaced from said chamber to provide an evacuated passage between said jacket and the walls of said chamber, a piston reciprocable in said chamber, means for introducing a combustible fuel into said chamber,

air inlet means associated with said combustion chamber, gas exhaust means associated with said chamber, a condenser, a heat exchanger, means for selectively directing a condensable exhaust gas from said gas exhaust means into said condenser and for directing a non-condensable exhaust gas into said heat exchanger, means for introducing air into said condenser to heat said air by heat exchange with the fluid flowing through said condenser, means for directing the heated air into said air inlet means, means for pressuring the condensate leaving said condenser, means for directing the condensate into said heat exchanger and into heat exchange relationship with the non-condensable gases flowing therethrough, and means for introducing the heated condensate from said heat exchanger into said combustion chamber.

7. In a power generating system, a combustion chamber, a heat insulating jacket about the chamber, said jacket being spaced from said chamber to provide an evacuated passage between said jacket and the walls of said chamber, a piston reciprocable within said chamber, means for introducing a combustible fuel into said chamber, air inlet means associated with said combustion chamber, gas exhaust means associated with said chamber, a condenser, a heat exchanger, means for selectively directing a condensable exhaust gas from said gas exhaust means into said condenser and for directing a References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 885,820 Winand et al Apr. 28, 1908 1,332,633 Parrish Mar. 2, 1920 1,339,176 Dyer May 4, 1920 1,509,622 Trent Sept. 23, 1924 1,682,307 Porter Aug. 28, 1928 2,057,075 Wuehr Oct. 13, 1936 2,202,480 Campbell May 28, 1940 FOREIGN PATENTS Number Country Date 261,084 Great Britain Nov. 11, 1926 

